Virtual reality experiences are becoming prominent. For example, 360° video is emerging as a new way of experiencing immersive video due to the ready availability of powerful handheld devices such as smartphones. 360° video enables immersive “real life”, “being there” experience for consumers by capturing the 360° degree view of the world. Users can interactively change their viewpoint and dynamically view any part of the captured scene they desire. Display and navigation sensors track head movement in real-time to determine the region of the 360° video that the user wants to view.
In packed projections such as a packed cube map, there may be discontinuity in one or more of the region boundaries in a 360° video which are not at the intersection of adjacent regions. During video rendering, texels from adjacent regions get used in texel interpolation leading to the discontinuity appearing as a boundary artifact in the rendered video.
One solution used to solve this problem is to use a guard margin at the region boundaries. However using the guard margin will lead to additional redundant texels in the transmitted video. Another solution is to extend the texels at the region boundaries. However, this leads to increased complexity at the decoder if texel extension is not supported in the rendering hardware. In order to provide implementation flexibility, a signaling mechanism is then needed to indicate whether guard margin is used at region boundary or whether padding is to be carried out.